22-04-2025
Itumeleng Molefe follows in his father's footsteps to unearth the links to humanity's deep past
Like his father before him and his cousin and his cousin's father, Itumeleng Molefe is a fossil technician at the Sterkfontein Caves, which contain one of the richest collections of hominin fossils in the world.
Itumeleng Molefe has one of those jobs that you probably have never heard of, but it is at the core of understanding and unearthing — literally — who we are as humans and how we've evolved.
Like his father before him, Molefe is a fossil technician at the Sterkfontein Caves, a dolomite cave system formed between 20 and 30 million years ago. Part of the Unesco-listed Cradle of Humankind, northwest of Johannesburg, the caves contain one of the richest collections of hominin fossils in the world.
Fossil technicians are behind the scenes of many major palaeoanthropological discoveries, responsible for much of the careful excavation, preparation and curation of fossil material, working closely with local and international researchers.
'I would say, generally speaking, fossil preparators are the foundation on which all of our sciences are based,' said Professor Dominic Stratford, a geoarchaeology lecturer at Wits University and research permit holder at the Sterkfontein Caves. 'Without fossil preparators, there would be no fossils, no material to analyse.'
Like many at the Sterkfontein Caves, Molefe comes from a line of fossil technicians.
'My cousin's father worked here; he was the first person to work here in our family,' said Molefe. 'And after that, he brought my father here.'
His father, Nkwane Molefe, became a fossil technician in 1972 and worked at the Swartkrans and Sterkfontein caves for 40 years.
Nkwane Molefe was part of the historic excavation of Little Foot, the most complete Australopithecus skeleton ever found.
In 1994, Professor Ronald Clarke discovered hominid foot bones in the Sterkfontein caves. In 1997, he enlisted technicians Stephen Motsumi and Nkwane Molefe to help locate the rest of the skeleton in the Silberberg Grotto in the Sterkfontein Caves. And they did.
'He gave Stephen and my father a piece of bone to match,' said Molefe. 'They put it on the rock — and it matched. Then they started digging and found the most complete skeleton in the world.'
About 90% of Little Foot's skeleton was preserved. The next most complete Australopithecus skeleton, 'Lucy', discovered in Ethiopia in 1974, is only 40% complete.
'It took 20 years to excavate to a point where we are now,' said Stratford. 'Initial stages isolated large blocks that could be removed and then the excavations carried on in the lab.'
Molefe's cousin Abel Molepolle and another fossil technician, Andrew Phaswana, worked on Little Foot in the casting lab with Clarke for almost 15 years.
Young Itumeleng spent his school holidays visiting the caves where his father worked.
'So he was always at the site as a child, always aware of what his father was doing and always exposed to what the fossil preparators were doing,' said Stratford. 'This was part of their family.'
After leaving high school, Molefe got a job in ventilation control at a platinum mine. When he was 29, he joined the Sterkfontein team, just a few months before his father retired.
One of Molefe's most exciting moments at Sterkfontein was when he found a hominin phalange (fingerbone) in 2015.
'We knew it was a phalange, so we took it to the casting lab, compared it to a model, only to find out it was hominin. Then we all got excited,' recalled Molefe. 'Joh, it was my happy time, that time.'
In 2017, while sorting through a bucket of material from Kromdraai — a nearby fossil site in the Cradle of Humankind — he discovered a trove of hominin teeth.
'I was just sorting material, only to find we had plenty of teeth. Not one — plenty. I can't count them,' he said. 'That day we were very, very excited.'
Stratford said, '[Molefe] is deeply invested and really proud of what he does, and of his dad and the contributions his family have made in Sterkfontein and to general discoveries in the Cradle. He's been incredible to work with.'
How do fossil technicians excavate? Slowly
Excavating fossils is a slow, delicate process. 'We try to excavate extremely slowly so we can document everything,' said Stratford.
The first step is capturing 3D coordinates with a laser survey device so any fossil can be precisely relocated. In soft sediment, brushes and trowels are used to expose the fossil. Once uncovered, it's documented and bagged or wrapped for lab analysis.
Most fossils in the Cradle of Humankind are found in hard breccia (a sedimentary rock). In these cases, entire blocks are removed to the lab, where technicians use air scribes — 'like a dentist's drill,' said Stratford — to chip away at the sediment, grain by grain, to reveal the fossil without damaging it.
'It's a really difficult thing to do, because the fossil is in most cases softer than the sediment around it,' said Stratford. 'So it's really easy to damage the fossil, and it takes years of experience to learn how to predict and understand where the fossil might be going.'
Stratford said fossil technicians often work blind, not knowing whether a visible fragment is part of a larger bone or just a shard. 'It's all very exploratory and all very gentle,' he said.
Lab preparation is preferred because of better lighting and controlled conditions. To prevent damage, fossils may be stabilised with paraloid — a reversible adhesive — or wrapped in bandages until they can be properly prepared in the lab.
In complex cases like Little Foot, where hundreds of bones are interwoven, the process can take years.
'Ron Clarke once described it as like excavating a delicate pastry pie from a block of cement,' said Stratford.
'If we think we've found something particularly interesting and it's too delicate to excavate, we can CT-scan the whole block and digitally excavate it. We can even 3D-print the fossil before doing any physical work.'
Learning through generations
'The really nice thing about Sterkfontein and its having such a long legacy of excavation is that most of the fossil technicians have been doing this as a family trade,' said Stratford.
'We joke that Abel was the last hominin to be born on Sterkfontein because he was actually born on the property,' added Stratford, referring to Abel Molepolle, who started working at the caves in 1999. Like his cousin Molefe and many others, Abel followed in his father's footsteps.
The specialised work of technicians is passed down through a combination of hands-on experience and formal training. The technicians gain skills through practical training and extensive fieldwork, often starting with apprenticeship-style learning and formal workshops in casting and fossil preparation.
'But now, people like Abel and Andrew are so good at what they do, we often go to them and ask how we should approach something or what part of the fossil we're dealing with,' said Stratford.
'They are some of the best fossil preparators and cast-makers in the world, actually, that I've worked with.'
Despite their expertise, some technicians haven't finished school. Molefe plans to begin the process of completing his matric in May.
Spotlighting technicians
At first, Molefe didn't realise the importance of his father's work at the caves.
'When I was coming here, there weren't many students. But after I joined under Dominic, more students were coming. I saw that my job is very important because of the Wits students, primary school students and high school students that come here, and we teach them,' he explained.
Visitors often ask how he distinguishes bones from rocks.
'The more you do something every day, the more you recognise it — you can do it with your eyes closed,' he smiled.
Despite the repetitive nature of the work, Molefe says it's never boring. 'Imagine you're looking for diamonds or gold — same like us. The more you excavate, the more you find bones, and the more excited you get.'
Stratford highlighted the vital role of the technical team, noting that their contributions were often overlooked. To recognise their efforts, he designed the new lab with a team wall on which technicians can share their own stories and experiences.
'Which are incredible and have changed their own lives but also changed, in many ways, all our lives — in terms of our understanding and accessibility to these incredibly rich stories of human evolution,' said Stratford.
With the reopening of the Sterkfontein Caves last week after a two-year closure caused by safety concerns, visitors can now also visit the laboratories at the site and see how fossils are prepared by the technicians.
'They are the lifeblood of the research,' Stratford said, stressing that more recognition and support were needed, particularly to secure funding for the technicians' salaries.
'It's easy enough to find money for a fancy piece of equipment or a student bursary, but finding funds for technical positions is really difficult. The more we can highlight them, the better.' DM
